Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013 Bed	Mar. 31, 2013 Hardeman County Correctional Facilities Corporation	Dec. 31, 1997 Hardeman County Correctional Facilities Corporation Facility
Loss Contingencies [Line Items]
Number of pending legal proceedings that would have an effect on consolidated financial position, results of operations, or cash flows	0
Issuance of revenue bonds			$ 72.7
Number of beds at the facility	92,500		2,016
Outstanding principal balance of revenue bonds		28.8
Outstanding principal balance of the bonds exceeded the purchase price option		$ 10.3